Australia could soon be fighting a war on two fronts after their pre‑Ashes stunt to project images of Ricky Ponting and Michael Clarke on to Big Ben spectacularly backfired, with Westminster city council last night responding with the threat of legal action.

The holographic image of Australia's captain and vice-captain beamed on to Big Ben on Wednesday evening carried the message "Don't forget to pack the urn", a brassy reference to the belief that their team will regain the Ashes by the time the five-Test series ends in Sydney during January. But the seemingly light-hearted stunt looks like landing them in serious hot water and possibly a police investigation.

Westminster city council's deputy leader, councillor Robert Davis, told Digger: "The Palace of Westminster is part of a Unesco world heritage site, and it's both inappropriate and insulting for this important location and its buildings to effectively be abused in this manner. It's also a criminal offence.

"If an organisation wishes to display advertising on it, or any other building in Westminster for that matter, they should apply through the normal channels like any right-minded person with respect for the law.

"Although we've not prosecuted previously as such stunts are usually over quickly, we do feel now that enough is enough and we're considering legal action.

"We also fear that without taking a firm stance this style of guerrilla advertising will only increase, particularly in the run-up to [the London Olympics in] 2012."

A Metropolitan Police source said that if a crime has been committed, it will investigate.

Cricket Australia was not available for comment last night but within an hour of the event the Australian game's governing body had issued a press release on its official website, highlighting the fact that the image had been projected.

It said: "An hour ago Ricky Ponting and Michael Clarke sent a stark warning to English cricket ahead of the up-coming Ashes series by watching over London from the tower of Big Ben. Images of the world-class duo were projected on to London's most iconic building accompanied by the words 'Don't forget to pack the urn – bringontheashes.com'."

Ponting added: "Winning the urn back from our age-old rival is the most prized achievement for Australians and we just wanted to send them a reminder not to leave the urn behind. Our message is clear – we're prepared and we're ready so bring on the Ashes."

It is not the first time Big Ben has been used as a canvas for projected images, with the TV presenter Gail Porter's buttocks famously the first in 1999. That, and other similar pranks, passed without prosecution from Westminster council.

However, with a £2,500 fine payable in the event of conviction at the magistrates courts over laws governing advertising consents, the council looks like making an example of Cricket Australia and its accomplices in a clear warning that it will now begin to protect its rights with a view to preventing repeats in the build-up to the 2012 Olympic Games.

Rooney's wage dilemma

Wayne Rooney's contract extension at Manchester United has presented the club with a tricky problem: to pay him what he wants may risk being unable to deliver the squad strengthening he has also demanded. Rooney's £180,000-a-week wage will add at least another £4.5m to the total staff costs. But while United think declining wages for some of the older players will ease things and point out that other players have at least two years on their contracts, Rooney's package has set a difficult new benchmark.

United's accounts, released this month, showed the wage bill had already risen from £123.1m in 2008-09, when they won the Premier League, to £131.7m last season, when they won only the Carling Cup. Other factors, not least a higher-rate tax increase from 40% to 50%, and the pound's weakness against the euro, the currency in which the big European clubs pay their players, will have a significant impact.

In their bond prospectus released in January, United stated: "There is a risk that – increasing player salaries and transfer fees [and Uefa's] financial fair-play initiative could limit our ability to acquire or retain top players and, therefore, materially adversely affect the performance of our first team."

Which all makes you wonder whether Rooney's little fit of pique ever really was about ambition at all.

Coe to run final furlong

The presence for England 2018 of David Beckham, David Cameron and Prince William at the Fifa vote on 2 December will give the bid an element of stardust. But it is the lobbying of those who are closest to the 24 decision makers who will make the most difference, and that is where the England 2018 board member Seb Coe comes in.

Due to the requirements of his day job as chairman of London 2012, Lord Coe has been unable to cover the ground others have put in. But he will be a key figure in the final furlong.

Coe is close to Sepp Blatter, with whom he first became acquainted at the International Olympic Committee, of which the Fifa president is a member. Coe is also well known to all 23 of the other Fifa executive-committee members and became the first-ever chairman of the its ethics committee in June 2006. At a time when that committee is at its busiest ever, Coe's presence in Zurich will no doubt be welcome.

Banks throw money at it

Banking is a dirty word. At least it has been since the 2007-08 financial crisis affected us all. And so what better way for banks to clean up their image with the common man than through the beautiful game? Sport+Markt, the research firm, yesterday showed that spending on shirt sponsorships by financial-services firms – plus the league's title sponsor – is much higher than in past seasons. There are now 10 shirt deals plus Barclays' title sponsorship, collectively worth about £88m to their beneficiaries this season. That is against about £38m last term and about £44m the year before, when Barclays' involvement was joined by only three other financial-services firms. But banks can afford to double their input into football. Many have spent the past three years winding down their exposure in lending to … football clubs.

Few English cricket fans would surely dissuade cCouncillor Davis from going through with it. ends